Brimonidine causes significantly more local allergic side effects than timolol
A meta-analysis from 2008 included 10 randomized clinical trials involving a total of 2387 patients. In all study settings, brimonidine 0.2% was compared to timolol 0.5% monotherapy for efficacy and adverse events. The age distribution of the data was 58-69 years and 60% had open-angle glaucoma and 37% had ocular hypertension.
Of the adverse reactions, local allergic reactions were statistically significantly less common in the timolol group than in the brimonidine group (RR 0.08, 95% CI 0.01-0.47). In contrast, there was no statistical difference in burning sensation and stinging between the groups.